The present invention relates generally to downhole sealing tools and methods for use in subterranean wells.
In the drilling and completion of oil and gas wells, a great variety of downhole tools are used. For example, but not by way of limitation, it is often desirable to temporarily seal tubing, casing, flow parts, or other tubulars in the well. The downhole tools are commonly used to isolate (seal off) a portion of a wellbore during cementing, formation treatment, and other well treatment processes. Downhole wellbore sealing tools such as packers, bridge plugs, tubing plugs, straddle packers, fracturing plugs, and cement plugs are designed for these general purposes and are well known in the art of producing oil and gas.
When it is desired to remove one of these downhole tools from a wellbore, it is frequently simpler and less expensive to drill it out using a cutting tool such as a drill bit rather than to implement a complex and sometimes unreliable retrieving operation.
However, drilling a tool out is a relatively expensive and time consuming process, especially when used to remove downhole tools having relative hard components such as erosion-resistant hard steel. To help reduce the drilling time, downhole tools have been developed that are easier to drill out by selecting designs that allow certain components of the tool to be made of a composite material. Such devices have worked well and provide improved operating performances at relatively high temperatures and pressures. However, removal of these types of tools from the well still requires further intervention in the well by reentering the well for drilling them out, with the accompanying drilling cost and disruption of production.
Improvements in the area of downhole wellbore sealing tools are still needed and the present invention is directed to that need.